Ethiopian Airlines: 'No survivors' on crashed Boeing 737 max

[LittleNelly]

As I’m understanding it, a STAB TRIM RUNAWAY is not the same as an MCAS activation.
Anyone else reading the same info from the numerous reports coming up with the same conclusion?
Boeing is going to take a $$bath$$ for rushing this aircraft to market.

Gino Under

Read the actual Lion Air report as this is the crash everyone seems to be basing everything off on. No fault to Boeing or the 737 reported in the Initial report.

STAB TRIM RUNAWAY is not a specific procedure. It covers ALL instances that might cause the stab trim to not function properly, ie it’s not doing as commanded. For instance the MCAS commands nose down trim if it detects a stall. If you’re not stalling and you don’t want the down trim the stall protection is commanding you follow your SOPs of carrying out The STAB TRIM RUNAWAY emergency checklist.

If you see the trim keep reverting to nose down after you move it up, what do would you do?
Start pondering the aeronautical engineering of the systems of your aircraft or carry out your emergency drill?
It’s not our job to determine the cause of a system failure, it’s to fly the plane safely, Follow SOP, do the emergency drill, land safely, file a report, and let maintenance determine the cause.

So yes unwanted MCAS commanded trim during a false stall indication is in FACT stab trim runaway.

Seriously, this whole thing was already dealt with. They found no fault in the 737Max with the Lion air initial report. 0. Boeings share of the fix was to tell airlines to remind crews to follow STAB trim runway checklist if the stab trim, well runsaway, as is the case during a false stall indication. It’s not rocket science.

This is all based on the Official reports. So what numerous reports are you referring to?

[Gino Under]

So, it seems some readers actually see the differences between two very different events. One, clearly a steady in put, easily dealt with while the other one, NOT so easily dealt with.
If investigators haven’t given us a conclusive finding yet for 2 apparent MCAS induced accidents, then my opinion is worthless. So are the opinions of numerous B737 pilots who ‘think’ THEY know the answer.

LittleNelly, are you really that confident in your statement regarding the Lion Air investigation? I’d pump the brakes on that if I were you.
Boeing is going to get skinned over this.
For starters. Have a read through this…
https://www.adn.com/nation-world/2019/0 ... ol-system/

If you like, I can send you a copy of the FAA AD that was issued within days of Lion Air accident. Based on the content of that AD, I’d have to disagree with your comments with respect to Boeing.

I don’t put much stock in paying too much attention to Standard operating procedures when I find myself in a situation that is anything other than STANDARD. Most reputable flight operations tell their aircrew SOPs can’t address every imaginable situation. It’s up to the crew to figure that out.
I suggest CRM and TEM is a better fit. Read the report on that United DC-10 at Sioux City back in the mid 80s or more recently, the Qantas A380 incident. Strict adherence to SOPs didn’t get those aircraft back on the ground, I can assure you.

Gino

[Eric Janson]

As I’m understanding it, a STAB TRIM RUNAWAY is not the same as an MCAS activation.
Anyone else reading the same info from the numerous reports coming up with the same conclusion?
Boeing is going to take a $$bath$$ for rushing this aircraft to market.

https://www.adn.com/nation-world/2019/0 ... ol-system/

Gino Under

I agree with you but some people hold a different view.

The aircraft is grounded for a reason - some people think this is an over-reaction.

A good article - pay attention to the bold text. This is why the certification is in jeopardy imho.

https://www.moonofalabama.org/2019/03/f ... .html#more

[ogc]

On one hand I see this is as basically a metro 2 with the rosemount system.

Single AOA attached to a stick pusher.

I think every metro pilot is well versed in the drill SAS clutch off.

On the other hand I see how crews weren't aware, Boeing didnt tell anyone really till after Lion Air.

[LittleNelly]

LittleNelly, are you really that confident in your statement regarding the Lion Air investigation? I’d pump the brakes on that if I were you.
Boeing is going to get skinned over this.
For starters. Have a read through this…
https://www.adn.com/nation-world/2019/0 ... ol-system/

If you like, I can send you a copy of the FAA AD that was issued within days of Lion Air accident. Based on the content of that AD, I’d have to disagree with your comments with respect to Boeing.


Gino

The anchorage daily news eh, because we all know the news never misreports or senstationalozes aviation stories.
Anyway you can check out my sources
The actual report from the official investigation https://reports.aviation-safety.net/201 ... MINARY.pdf
Or the avherald has a summary of it if you don’t feel like reading the whole report
http://avherald.com/h?article=4bf90724/0009&opt=0

See if you can find them blaming the 737..

No need to send me the AD, here it is
http://rgl.faa.gov/Regulatory_and_Guida ... ection.pdf

Basically the remedy is emphasizing that uncommanded horizontal stabilizer movement=RUNAWAY STABILIZER

So this is a serious question.. in your opinion, in an event where the stab trim has uncommanded nose down movement, it is not the pilots fault for not actioning the runaway stab trim drill?

So yes following SOPs and emergency checklists would have brought the plane safely home.. because they did that exact thing the night before! Then Lion air cut corners and sent out an ‘unairworthy aircraft’(according to the Indonesian investigators) the next day ending in the crash.

[Gino Under]

LittleNelly

Thanks for the reply. (and lack of hostility)
This article was published in the Seattle Times. I didn’t want to buy an online subscription so I googled it and the nice folks in Alaska have it in on their website, which was free, so there we go. The wild and whacky internet, eh? I must agree though, it’s wise to be suspicious of news reports these days, now that we suddenly find ourselves in the “fake news” era.

I wondered why the inbound Lion Air crew, who had dealt with an instability issue, wrote it up, it was subsequently cleared by their Mtce and the aircraft released? Why also wasn’t there any face-to-face communication between the inbound and outbound crews? But alas, too late.
As I see it, and I am in no way an expert on this, a stab trim runaway generally is an electrical issue and stab movement through MCAS is due to erroneous AoA input. The same thing, only different as proven by two horrific accidents with no definitive cause identified. Every B737 pilot (including me) is proficient, knowledgeable, and aware of how to deal with a Stab Trim Runaway.

The MAX should be grounded. That’s not hysteria, or fake news. It’s common sense.
The evidence just gets stronger by the day.

GU

[FICU]

Boeing has no redundancy on some parts. MCAS for example, works with ONLY the left side AOA probe. No comparison, so agreement required, just one prope. Single point of failure.

This is the main issue. Had there been a second or third AoA input required to trigger the MCAS we probably wouldn’t be talking about any of this.

Unfortunately we seem to have had 2 crews who couldn’t manage the stab trim due to the MCAS reacting to a false AoA input.

[Flying Low]

The only difference between a Stab Trim Runaway and the MCAS situation is that the pilot can intervene with the electric trim and stop it momentarily.

Would you keep trying to fly with an autopilot that wasn't doing what you wanted or use an auto throttle system that wasn't giving you the results you were looking for? I sincerely hope the answer is a NO!

The Lion Air crew flew around with a malfunctioning trim for the better part of ten minutes before completely losing control of the aircraft and never thought to turn the electric trim off?

My biggest question about this isn't about Boeing's design of the MCAS but the training of a crew that would continue to use a malfunctioning system for 10 minutes.

Sort of like the Sunwing crew in Belfast that let the plane fly itself , without manually adding any extra throttle.

Exactly...we are suppose to be able to operate these aircraft utilizing all or none of the automation (or any level in between) and make decisions on how much automation to use and to recognize when to stop using it. Yes, Boeing should have been a lot more informative about this new system but the question still remains...how long do you continue to use a malfunctioning system before you turn it off? As for the Ethiopia accident...I have heard no information (except that the accident is similar to Lion Air) so I have no idea what kind of time span that crew had to deal with this situation.

[FICU]

It’s exactly the same. If the stab trim is running on its own in the opposite direction you want it to, you treat it as a runaway. Dont try to analyze why it is doing what it is in the moment just cut power to it.

As an FYI the stab trim runaway QRC is all memory action right to moving the cut off switches to the cut off position.

As I’m understanding it, a STAB TRIM RUNAWAY is not the same as an MCAS activation.
Anyone else reading the same info from the numerous reports coming up with the same conclusion?
Boeing is going to take a $$bath$$ for rushing this aircraft to market.

https://www.adn.com/nation-world/2019/0 ... ol-system/

[sportingrifle]

I think Boeing is probably facing a potentially bigger issue than the failure of the MCAS system. The bigger issue is that it is becoming increasingly apparent that the FAA failed to provide adequate oversight of delegated certification functions. What Boeing really needs to fear (apart from the punitive damages from the lawsuits) is that the airplane will have to undergo a complete re-certification. And even if senior FAA officials are satisfied, I am not sure that other world authorities, especially the European JAA are going to take the FAA's word on it this time.

[A346Dude]

I'm a little surprised by the number of pilots willing to defend a system as poorly thought out as MCAS. With a single point failure, it will actively yet subtly try to kill you, while providing multiple, possibly conflicting warnings. It has a foreseeable and severe failure mode that never should have made it into a production airplane.

[FICU]

Regardless of the faults in the design of the MCAS AoA input it should not have resulted in 2 hull losses.

[Eric Janson]

It’s exactly the same. If the stab trim is running on its own in the opposite direction you want it to, you treat it as a runaway. Dont try to analyze why it is doing what it is in the moment just cut power to it.

As an FYI the stab trim runaway QRC is all memory action right to moving the cut off switches to the cut off position.

So you're going to use the cut-out switches when the Speed Trim and/or Mach Trim move the Stabilser?

In the Lion Air crash the stickshaker was operating continuously which would mask the sound of the trim wheel moving. This in addition to multiple Master Cautions giving failures messages that may add to the confusion (just look at the message list on the Boeing advisory). All this while the crew is fighting to control an aircraft that is getting nose heavy.

Don't forget this crew knew nothing about MCAS - a previous write up incorrectly identified this as a problem with the Speed Trim.

I can see why a crew would become overloaded in this situation and once the stabiliser reaches full nose down the nose down input cannot be over-riddden by elevator input. If you are low then you won't have enough time to recover.

I'm surprised that people continue to believe this failure is nothing to worry about. Fortunately the decision makers at various Airlines and Regulators around the World hold a different view.

[FICU]

So you're going to use the cut-out switches when the Speed Trim and/or Mach Trim move the Stabilser?

We are talking uncommanded runaway not normal operations of minor trim inputs.

Let's try to use some common sense here.

[J31]

So you're going to use the cut-out switches when the Speed Trim and/or Mach Trim move the Stabilser?

We are talking uncommanded runaway not normal operations of minor trim inputs.

Let's try to use some common sense here.

TWO hull losses with nearly 350 people dead! Common sense is there is something really wrong here!

Have you flown the 737 with speed trim? Lots of us have and can easily see how this scenario can overwhelm a crew.

[LittleNelly]

Gino under

Sorry if my post came across as hostile, I didn’t intend it to.

My main point is these are not my opinions but the facts, not as reported by random news agencies, but from investogators and regulators.

The idea that uncommanded stab trim movement(regardless of what system is creating the movement) is actioned by the stab trim runaway checklist is not my opinion. It is the opinion of Boeing, the FAA, Transport canada, EASA, CAA of China, every other aviation regulator around the world, as well as every airline in the world that operates the Max.

After Lion air all those people were aware that the Max stall protection system utilizies trim but they also concluded that it was a reasonable assumption that flight crews would action their memory items and emergency checklist for trim runaway in the event of uncommanded trim movement. Whether it’s the MCAS or the flight control system giving eranous commands is irrelevant to our actions. That’s the opinion of all those regulators, they all agreed with Boeing.

What changed with Ethiopian. Well now maybe we can’t assume flight crews will preform their emergency actions. So how does that get remedied. Well once we figure that out, it’ll be an autonomous airliner.

But anyway every single issue being discussed right now in regards to the Max has already been discussed. Every regulator accepted pilots should know how to recognize uncommanded stab trim movement.

Boeing for sure will want to make whatever updates and changes to help out but that in no way puts the cause on them anymore than Airbus changing the pitot tubes on the 330s after Air France 447.

[goingmach_1]

Not a Boeing pilot, all corporate stuff for me. The trim “runaway” is quite manageable as soon as it is recognized on the current machine I am flying F-900LX. The Falcon has no stick shaker or pusher, though the Challenger 601/605 I have also flown did.

Read most of the informative posts on this thread, skipped the irrelevant stuff, so might have missed a piece of info.

I have a couple of questions for those in the know.

1. Does the MCAS only function with autopilot off? (In other words, when being hand flown)

2. Does the MAX have a stick shaker/pusher?

[C-GGGQ]

1 yes autopilot off, flaps up, high AOA
2 yes

[FICU]

Have you flown the 737 with speed trim? Lots of us have and can easily see how this scenario can overwhelm a crew.

I have been for many, many years.

If the trim is trying to drive you into the ground regardless of what system is running it... Kill the trim.

[Heliian]

Have you flown the 737 with speed trim? Lots of us have and can easily see how this scenario can overwhelm a crew.

I have been for many, many years.

If the trim is trying to drive you into the ground regardless of what system is running it... Kill the trim.

Well, just put a sticky label on the dash and call er good!